The present invention relates to a micro-electromechanical actuator. An electromagnetic-type micro-electromechanical actuator of the present invention has a conductive beam formed in a micro electronic substrate on an upper side of a magnetic substance, so that the conductive beam can be moved toward an in-plane mode in parallel to the micro electronic substrate depending on a direction that current flows. Therefore, the micro-electromechanical actuator can be applied to most of electromagnetic micro-electromechanical systems that require an in-plane mode.